JP7317547B2 - FUEL CELL STRUCTURE, FUEL CELL MODULE AND FUEL CELL DEVICE INCLUDING THE SAME - Google Patents

Description

The present invention relates to a fuel cell structure, a fuel cell module having the same, and a fuel cell device.

As is well known, in a fuel cell, an anode electrode layer and a cathode electrode layer are formed with an electrolyte layer interposed therebetween, a reducing gas is supplied to the anode electrode layer, and an oxygen-containing gas is supplied to the cathode electrode layer. Supplied to generate electricity. The former is called a fuel gas supply channel, and the latter is called an oxidizing gas supply channel.
Techniques related to this type of fuel cell include the techniques disclosed in Patent Documents 1 and 2 below.

Patent Document 1 discloses an electrochemical device E that can be employed as a fuel cell. This electrochemical element E corresponds to the fuel cell structure in the present invention (see FIG. 2 of the specification), and a plurality of these electrochemical elements E are laminated to form an electrochemical module M (in the present invention). corresponding to a fuel cell module) is formed. Furthermore, this electrochemical module is combined with other devices to form an electrochemical device (corresponding to the fuel cell device of the present invention) (see FIG. 1).

The electrochemical element E has a conductive tubular support 31 and an electrochemical reaction section 43 (corresponding to a fuel cell in the present invention), and the electrochemical reaction section 43 is a membrane electrolyte layer. 46, a film-like fuel electrode 44 (corresponding to the anode electrode layer in the present invention), and a film-like air electrode 48 (corresponding to the cathode electrode layer in the present invention). The cylindrical support 31 is arranged between the air electrode 48 and includes a gas flow permitting portion P2 that allows gas to flow between the inside and outside of the support 31, and a space between the inside and outside of the metal support 1. The electrochemical reaction part 43 is arranged outside or inside the metal support 1 to cover part or all of the gas flow-permitting part P2. be done.
Therefore, the electrochemical element E has a structure in which the fuel gas supply path described above is formed in the cylindrical support 31. As shown in FIG. For example, in the structure shown in FIG. 5 of the same specification, the fuel gas flows in one direction from the bottom to the top of the drawing.

Patent Literature 2 proposes to provide a fuel cell that can prevent both excessive temperature rise and temperature unevenness during power generation without sacrificing power generation performance. For the purpose, a fuel supply channel (corresponding to the "fuel gas supply channel" of the present invention) (210, 125). A reforming catalyst part PR<b>1 for causing a steam reforming reaction is provided in the fuel supply channel on a surface facing the fuel electrode 112 while being spaced apart from the fuel electrode 112 .

In this technique, the reformed gas reformed in the reforming catalyst part PR1 is introduced into the fuel electrode. The reformed gas is consumed at the fuel electrode and discharged from the outlet of the fuel supply channel. Therefore, by utilizing the fact that the steam reforming reaction is an endothermic reaction (requires heat supply), an increase in the temperature of the fuel cell is prevented. Here, the part where the reforming catalyst part PR1 is provided is the part on the upstream side of the fuel gas supply with respect to the fuel electrode. is discharged through a separate exhaust channel.
Furthermore, judging from the drawings and the like, the fuel cell disclosed in Document 2 is a so-called anode electrode-supported fuel cell in terms of its structure.

JP 2016-195029 A JP 2017-208232 A

The techniques disclosed in Patent Documents 1 and 2 have the following problems.
In the technique disclosed in Patent Document 1, in the structure formed in the tubular support 31, for example, in the structure shown in FIG. There is room for improvement for the purpose of easily flowing and supplying the reducing gas to the anode electrode layer.

In the anode-supported fuel cell disclosed in Patent Document 2, the anode electrode layer is thick (generally on the order of several millimeters), and the internal reforming reaction proceeds at once at the inlet portion where the fuel gas is introduced. As a result, the inlet temperature of the fuel cell becomes low, and the exhaust side is maintained at the original temperature of the fuel cell. is easy to come out.
Furthermore, water vapor is generated in the cell reaction, but if the fuel cell is of the oxide ion conduction type, the exhaust after the cell reaction does not pass through the reforming catalyst and is discharged from the exhaust flow path. It is not usefully utilized in the reaction.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to realize a fuel cell structure capable of reliably supplying fuel gas to an anode electrode layer.

The first characteristic configuration of the present invention is
a fuel cell in which an anode electrode layer and a cathode electrode layer are formed with an electrolyte layer sandwiched therebetween;
A structure capable of forming a fuel cell single cell unit, comprising a fuel gas supply path for supplying a reducing gas to the anode electrode layer and an oxidizing gas supply path for supplying an oxygen-containing gas to the cathode electrode layer. and
The fuel gas supply path is provided with a turbulence promoter for disturbing the flow in the fuel gas supply path and an internal reforming catalyst layer for reforming the raw fuel gas.

As described above, the gas flow in the fuel gas supply channel tends to be laminar due to its channel structure. , a direction different from the main stream direction (for example, a flow orthogonal to the main stream) can be formed with respect to the main stream formed in the fuel gas supply passage. As a result, the reducing gas can be efficiently supplied to the anode electrode layer.

On the other hand, in an oxide ion conductive fuel cell in which water vapor is generated in the anode electrode layer, the release of the generated water vapor from the vicinity of the anode electrode layer can be effectively promoted. By providing an internal reforming catalyst layer in the fuel gas supply path, steam generated by power generation can be effectively utilized for reforming (mainly steam reforming). When the fuel cell is of the proton-conducting type, internal reforming can be performed in the internal reforming catalyst layer and supplied to the anode electrode layer.

The second characteristic configuration of the present invention is
The fuel cell is formed in layers on a support,
A plurality of through-holes penetrating through the support are provided,
The anode electrode layer is provided on one surface of the support, and the fuel gas supply path is provided along the other surface.

According to this characteristic configuration, the anode electrode layer of the fuel cell is provided on one side of the support, and the fuel gas supply path is provided on the other side of the support. It can favorably promote the supply and release of gas. Furthermore, when water vapor is generated in the anode electrode layer, this water vapor can be returned to the fuel gas supply channel, and the reforming inside the fuel cell structure can proceed satisfactorily.

The third characteristic configuration of the present invention is
The internal reforming catalyst layer is provided on at least part of the inner surface of the fuel gas supply passage.

According to this characteristic configuration, it is possible to realize a fuel gas supply path provided with an internal reforming catalyst layer with a relatively simple configuration in which the internal reforming catalyst layer is formed in at least a part of the reducing gas supply path.

The fourth characteristic configuration of the present invention is
The point is that the internal reforming catalyst layer is provided inside the through hole.

According to this characteristic configuration, the gas flowing through the through-hole can be used to reform the gas flowing through this portion.

The fifth characteristic configuration of the present invention is
comprising at least one separator separating the fuel gas supply channel and the oxidizing gas supply channel;
The feature is that the internal reforming catalyst layer is provided on at least a part of the separator on the fuel gas supply path side.

According to this characteristic configuration, by stacking the fuel cell structures, it is possible to form a fuel gas supply path on one side and an oxidizing gas supply path on the other side with the separator sandwiched therebetween, A fuel cell (specifically, a fuel cell module) can be constructed with a relatively simple structure, and as a result, a highly reliable and long-life fuel cell can be obtained.

The sixth characteristic configuration of the present invention is
The reforming catalyst contained in the internal reforming catalyst layer is a catalyst in which a metal is supported on a carrier.

According to this characteristic configuration, by using a catalyst in which a metal is supported on a carrier, a high-performance internal reforming catalyst layer can be obtained even if the amount of metal used in the catalyst is reduced, resulting in low cost. , a high-performance fuel cell device can be obtained.

The seventh characteristic configuration of the present invention is
The reforming catalyst contained in the internal reforming catalyst layer is a catalyst containing Ni.

According to this characteristic configuration, steam reforming can occur in the internal reforming catalyst layer using Ni, which is a relatively easily available and inexpensive metal.

An eighth characteristic configuration of the present invention resides in that the turbulence promoter is a mesh.

According to this characteristic configuration, the mesh-shaped turbulence promoting body disturbs the gas flow that hits the mesh-like body while maintaining the main stream of the flow in the fuel gas supply passage to some extent, and moves toward the anode electrode layer. In a configuration in which a flow is formed and water vapor is generated from the electrode layer, this water vapor can be released to the mainstream side.

The ninth characteristic configuration of the present invention is
A plurality of through-holes penetrating through the support are provided,
The anode electrode layer is provided on one surface of the support, and the fuel gas supply path is provided along the other surface,
The point is that the mesh-like body is provided on the other side of the fuel gas supply passage.

According to this characteristic configuration, since the mesh-like body is arranged in the vicinity of the through-holes penetrating through the support, the mesh-like body allows the gas to flow to the anode electrode layer through the through-holes and further from the electrode layer. Good flow can be generated.

A tenth characteristic configuration of the present invention is
The turbulence promoter is a plurality of obstacles arranged in the fuel gas supply passage.

With this characteristic configuration, the flow in the fuel gas supply passage becomes a flow that passes between a plurality of obstacles, but it is possible to form complicated flows with different flow directions in the fuel gas supply passage, resulting in A flow to the anode electrode layer and a flow from the anode electrode layer can be efficiently generated.

The eleventh characteristic configuration of the present invention is
A reforming catalyst is carried on at least a part of the surface of the turbulent flow promoting body, and the internal reforming catalyst layer is formed.

According to this characteristic configuration, in addition to the control of the flow in the fuel gas supply passage by the turbulence promoter, which has been explained so far, the reforming can be performed by the turbulence promoter.

A twelfth characteristic configuration of the present invention is
The point is that the support is formed using a metal material.

According to this characteristic configuration, the metal material has high strength and excellent formability. As a result, the support can be formed thin. Therefore, a compact, lightweight, and low-cost fuel cell structure can be obtained.

The thirteenth characteristic configuration of the present invention is
The feature lies in that the turbulence promoter is formed using a metal material.

According to this characteristic configuration, the metal material has high strength and excellent formability. As a result, the turbulence promoter can be formed thinly and in any shape. Therefore, a compact, lightweight, and low-cost fuel cell structure can be obtained.

A fourteenth characteristic configuration of the present invention is
It is in that the said separator is formed using the metal material.

According to this characteristic configuration, the metal material has high strength and excellent formability. As a result, the separator can be formed in any shape and thinly. Therefore, a compact, lightweight, and low-cost fuel cell structure can be obtained.

A fifteenth characteristic configuration of the present invention is
The point is that the fuel cell is a solid oxide fuel cell.

According to this characteristic configuration, the heat of the solid oxide fuel cell that operates at high temperature can be used for internal reforming, and special additional reforming is performed for removing carbon monoxide that may be contained in the reformed gas. This reformed gas can be directly supplied as a fuel gas to a solid oxide fuel cell to generate power without passing through equipment. As a result, the fuel cell device can have a simple configuration.

The sixteenth characteristic configuration of the present invention is
configured with a plurality of the fuel cell structures described so far,
The oxidizing gas supply path of one of the fuel cell single cell units supplies the oxygen-containing gas to the cathode electrode layer of the other fuel cell single cell unit adjacent to the one fuel cell single cell unit. The reason is that the fuel cell module is configured to

According to this characteristic configuration, when constructing a fuel cell module by stacking a plurality of fuel cell single cell units (which may be vertically stacked or horizontally arranged side by side), one fuel By using the oxidizing gas supply path that can be formed in the battery single cell unit as a supply source of the oxidizing gas to the cathode electrode layer of the fuel cell unit that constitutes another fuel cell single cell unit, other members are not particularly required. A fuel cell module can be constructed using a relatively simple and standardized fuel cell single cell unit.

The seventeenth characteristic configuration of the present invention is
The fuel cell device comprises at least the fuel cell module and an external reformer, and a fuel supply section for supplying the raw fuel gas to the fuel cell module.

According to this characteristic configuration, since it has a fuel cell module and an external reformer, and has a fuel supply section that supplies raw fuel gas containing a reducing component to the fuel cell module, existing gas such as city gas By using the raw fuel supply infrastructure, it is possible to realize a fuel cell device having a fuel cell module with excellent durability, reliability and performance. Moreover, since it becomes easy to construct a system for recycling unused fuel gas discharged from the fuel cell module, a highly efficient fuel cell device can be realized.

The eighteenth characteristic configuration of the present invention is
The fuel cell device is configured to have at least the fuel cell module and an inverter for extracting power from the fuel cell module.

According to this characteristic configuration, the power generated in the fuel cell can be taken out via the inverter, and the generated power can be used appropriately by performing power conversion, frequency conversion, and the like.

Schematic diagram showing the overall configuration of the fuel cell device Explanatory diagram showing the supply structure of fuel gas and oxidizing gas in a fuel cell module FIG. 2 is a cross-sectional perspective view showing a part of a fuel cell module formed by combining a pair of fuel cell structures; FIG. 2 is a cross-sectional perspective view showing a part of a fuel cell module formed by combining a pair of fuel cell structures; Explanatory drawing showing gas flow and reaction around the fuel gas supply path Figure showing another embodiment of the turbulence promoter A diagram showing another embodiment in which an internal reforming catalyst layer is provided on the surface of the turbulence promoter. FIG. 3 shows another embodiment employing a fuel cell structure with a different structure;

Hereinafter, the present invention will be described in the order of a fuel cell device Y, a fuel cell module M provided in the fuel cell device Y, and a fuel cell single cell unit U constructed by stacking the fuel cell modules M, based on the drawings.

FIG. 1 is a schematic diagram showing the overall configuration of a fuel cell device Y, showing a fuel gas supply system FL, an oxidizing gas supply system AL, and an anode off-gas circulation system RL each connected to a fuel cell module M, which is a fuel cell main body. ing.
In the fuel cell module M, one fuel cell single cell unit U is schematically shown, which is stacked in plurality to form the fuel cell module M. As shown in FIG. The fuel cell single cell unit U is provided with fuel cells R. As shown in FIG. The fuel cell single cell unit U, the fuel cell R, and the like will be described later in detail, including the manufacturing method thereof. A basic unit constituting the fuel cell single cell unit U is the fuel cell structure of the present invention.

FIG. 2 is a schematic cross-sectional view showing the structure of the fuel cell module M. Fuel gas, which is a gas containing hydrogen, is supplied around the metal support 1 and the metal separator 7 that constitute the fuel cell single cell unit U. 1 shows the form and supply form of an oxidizing gas containing oxygen.

In the figure, description of the fuel cell R is omitted for easy understanding.

<Fuel cell device>
The fuel cell device Y is configured as a so-called cogeneration system (thermoelectric parallel supply system), and has a heat exchanger 36 as an exhaust heat utilization unit that utilizes the heat emitted from the fuel cell device Y. An inverter 38 is provided as an output conversion unit for outputting electric power generated by the battery device Y. As shown in FIG.

The control unit 39 controls the operation of the entire fuel cell device Y according to the power load required for the fuel cell device Y. FIG. Each device to be controlled will be described in the description of the device. Input information to the control unit 39 is activation start/activation stop information of the fuel cell device Y and the power load required for the device Y. FIG.

The fuel cell device Y comprises a fuel cell module M, a fuel gas supply system FL, an oxidizing gas supply system AL and an anode off-gas circulation system RL. The fuel gas supply system FL corresponds to the fuel supply section of the present invention.

The fuel gas supply system FL includes a booster pump 30, a raw fuel gas supply system FLa equipped with a desulfurizer 31, a reformed water tank 32, and a steam supply system FLb equipped with a reformed water pump 32p and a vaporizer 33. It has

In this embodiment, the raw fuel gas supply system FLa and the water vapor supply system FLb are joined to the anode off-gas circulation system RL. and water vapor. The external reformer 34 is connected to the fuel gas supply path L1 formed in the fuel cell single cell unit U constituting the fuel cell module M on its downstream side.

The booster pump 30 boosts the pressure of a hydrocarbon-based gas such as city gas (a gas containing ethane, propane, butane, etc., with methane as the main component), which is an example of the raw fuel gas, and supplies it to the fuel cell device Y. In this supply mode, an amount of raw fuel gas corresponding to the power load required for the fuel cell device Y is supplied in accordance with a command from the control unit 39 .

The desulfurizer 31 removes (desulfurizes) sulfur compound components contained in city gas or the like. If the raw fuel gas contains sulfur compounds, the provision of the desulfurizer 31 can suppress the influence of the sulfur compounds on the external reformer 34 or the fuel cell single cell unit U.

This desulfurizer 31 accommodates a copper-zinc desulfurizing agent, and the sulfur component contained in the raw fuel gas has a sulfur content of 1 vol. ppb or less (more preferably 0.1 vol.ppb or less). As this type of copper-zinc desulfurizing agent, copper oxide-zinc oxide prepared by a coprecipitation method using a copper compound (e.g., copper nitrate, copper acetate, etc.) and a zinc compound (e.g., zinc nitrate, zinc acetate, etc.) A desulfurizing agent obtained by hydrogen reduction of the mixture, or a copper oxide-zinc oxide-aluminum oxide mixture prepared by a coprecipitation method using a copper compound, a zinc compound and an aluminum compound (e.g., aluminum nitrate, sodium aluminate, etc.) A desulfurizing agent obtained by hydrogen reduction can typically be used.

The reforming water tank 32 stores reforming water (basically pure water) in order to supply steam necessary for steam reforming in the external reformer 34 . The supply mode is to supply the amount of fuel gas according to the command from the control unit 39 in order to obtain the fuel gas that matches the power load required for the fuel cell device Y. FIG. However, as will be explained later, in the fuel cell device Y of the present invention, the water vapor contained in the anode off-gas can cover the water vapor required for steam reforming in a steady operation state in which power is generated in accordance with a normal electric power load. Therefore, the supply of reformed water from the reformed water tank 32 and the vaporization in the vaporizer 33 mainly play a role when the fuel cell device Y is started.

The vaporizer 33 converts the reforming water supplied from the reforming water tank 32 into steam. The external reformer 34 steam-reforms the raw fuel gas desulfurized by the desulfurizer 31 using the steam generated by the vaporizer 33 to produce a reformed gas containing hydrogen. However, since the internal reforming catalyst layer D is provided in the fuel cell single cell unit U of the present invention, the raw fuel gas is also reformed in this unit U. As a result, in the external reformer 34, part of the raw fuel gas is reformed, and the remainder is supplied to the fuel gas supply path L1 of the fuel cell single cell unit U as it is.

A steam reforming catalyst is housed in the external reformer 34, and examples of this type of catalyst include ruthenium-based catalysts and nickel-based catalysts. More specifically, a Ru/Al ₂ O ₃ catalyst obtained by supporting a ruthenium component on an alumina carrier, a Ni/Al ₂ O ₃ catalyst obtained by supporting a nickel component on an alumina carrier, and the like can be used.

Now, the operating operation in the steady operation state in which the fuel cell device Y continuously generates power according to the electric power load will be described below.
Since the fuel cell in this embodiment is of the oxide ion conduction type, the exhaust gas (anode off-gas) discharged from the fuel gas supply path L1 provided in the fuel cell single cell unit U contains water vapor. Therefore, an operation mode is adopted in which this gas is cooled, excessive water is condensed and removed, the steam partial pressure is adjusted, and the anode off-gas is returned to the external reformer 34 and used for steam reforming.

That is, the fuel cell device Y is provided with an anode offgas circulation system RL, and the anode offgas circulation system RL includes a cooler 32a for cooling the anode offgas flowing inside, and a cooler 32a for further cooling and removing condensed water from the anode offgas flowing inside. A condenser 32b for adjusting the partial pressure of water vapor and a heater 32c for raising the temperature of the anode off-gas to be returned to the external reformer 34 are provided.

By adopting this structure, the circulation pump 32d is actuated so that the amount of steam introduced into the external reformer 34 can be made closer to the gas circulated through the anode off-gas circulation system RL. When adopting this structure, by adjusting the condensation temperature in the final-stage condenser 32b, it becomes possible to adjust the partial pressure of water vapor circulating through the anode offgas circulation system RL. The water vapor/carbon ratio (S/C ratio) can be controlled for the gas being treated.

In this circulation mode, the external reformer 34 can supply the amount of steam required when at least part of the raw fuel gas is reformed by the external reformer 34 to meet the power load required for the fuel cell device Y. An appropriate S/C ratio is obtained, and the operation follows a command from the control unit 39 .
The objects to be controlled here are the setting and control of the amount of circulation by the circulation pump 32d, pressure setting, and condensation temperature (resulting in outlet water vapor partial pressure) in the condenser 32b, which is the final stage of cooling.

A blower 35 is provided in the oxidizing gas supply system AL, and is connected to the oxidizing gas supply path L2 formed in the fuel cell single cell unit U constituting the fuel cell module M at its downstream side. The amount of air sucked by the blower 35 also ensures a sufficient amount of air to cause the power generation reaction in the fuel cell in accordance with the power load, and the operation follows the command from the control unit 39 .

<Fuel cell module>
The fuel cell module M includes a fuel gas, which is a "hydrogen-containing gas" that is an example of reducing gas supplied via the external reformer 34, and "oxygen" supplied from the oxidizing gas supply system AL. Using the oxidizing gas, which is the contained gas, a battery reaction is caused to generate electricity. As for the exhaust gas discharged from the fuel cell module M, the anode off-gas was circulated to the external reformer 34 via the anode off-gas circulation system RL, and as for the cathode off-gas, exhaust heat recovery in the heat exchanger 36 was completed. After that, it is released to the outside.

FIG. 2 shows a supply form of fuel gas and oxidizing gas in a fuel cell module M configured by arranging a plurality of fuel cell single cell units U side by side. , and gas manifolds 40a and 40b, respectively.
A plurality of fuel cell single cell units U are arranged side by side while being electrically connected to each other, and both ends (left and right ends) of the fuel cell single cell units U are fixed to gas manifolds 40a and 40b. As is clear from the above description, the fuel gas distribution system and the oxidizing gas distribution system are completely independent. A fuel gas is supplied through the gas supply path L1, and an oxidizing gas is supplied to the cathode electrode layer C through the oxidizing gas supply path L2.
A fuel gas distribution system and an anode off-gas discharge system are indicated by solid lines, and an oxidizing gas distribution system and a cathode off-gas discharge system are indicated by dashed lines.

End collector members 41a and 41b are provided at both ends (upper and lower ends in FIG. 2) of the plurality of fuel cell single cell units U in a stacked state, so that the plurality of fuel cell single cell units U are arranged in series. The power generated by U is tapped and sent to the inverter 38 where it undergoes a predetermined conversion process. The inverter 38, for example, adjusts the output power of the fuel cell module M to have the same voltage and frequency as the power received from the commercial system (not shown).

<Fuel cell single cell unit>
3 and 4 are cross-sectional perspective views showing part of a fuel cell module M formed by combining a pair of fuel cell single cell units U. FIG.
FIG. 3 is perpendicular to the flow direction of the gas flowing through the fuel gas supply path L1 and the oxidizing gas supply path L2 formed by sandwiching the fuel cell R and the metal support 1 (indicated by black arrows and hollow arrows). It shows a cross section in the direction of FIG. 4 is a diagram showing a cross section along the flow direction of both gases.
The cross-sectional position of these drawings is the position where the through hole 1a is provided in FIG. 3, and that in FIG.
As can be seen from these figures, the inner surface of the fuel gas supply path L1, that is, the surface of the metal separator 7 (upper surface of FIGS. 3 and 4) serving as the fuel gas supply path L1, has one of the features of the present invention. A characteristic internal reforming catalyst layer D is provided. Furthermore, a net-like body Ea as a turbulence promoter E is provided on the lower surface of the metal support 1 .
As described above, the fuel cell R and the fuel cell module M are substantially rectangular.

The fuel cell single cell unit U includes a fuel cell R formed on the metal support 1 and a metal separator 7 joined to the opposite side of the fuel cell R. As shown in FIG.

The metal support 1 has a substantially rectangular shape, and the fuel cell R comprises at least an anode electrode layer A, an electrolyte layer B, and a cathode electrode layer C, and is formed and arranged on the front side of the metal support 1 . The electrolyte layer B is sandwiched between the anode electrode layer A and the cathode electrode layer C. As shown in FIG. When the fuel cell R is formed on the front side of the metal support 1 , the metal separator 7 is positioned on the back side of the metal support 1 . That is, the fuel cell R and the metal separator 7 are positioned with the metal support 1 sandwiched therebetween.

The fuel cell single cell unit U includes the fuel cell R formed on the metal support 1 and the metal separator 7, so that at least the fuel gas is oxidized to the anode electrode layer A through the fuel gas supply path L1. An oxidizing gas is supplied to the cathode electrode layer C through the oxidizing gas supply path L2 to generate electricity.

Further, as a structural feature of the fuel cell single cell unit U, the metal oxide layer x is formed on the front side of the metal support 1, and the surface of the anode electrode layer A (the interface between the anode electrode layer A and the electrolyte layer B covering it). ) is provided with an intermediate layer y, and the surface of the electrolyte layer B (including the interface between the electrolyte layer B and the cathode electrode layer C covering it) is provided with a reaction prevention layer z. These metal oxide layer x, intermediate layer y, and reaction prevention layer z are layers provided for suppressing diffusion of constituent materials between material layers sandwiching these layers x, y, and z (FIG. 5 to be described later). reference).

<Metal support>
The metal support 1 is a rectangular plate made of metal.
As can be seen from FIGS. 3 and 4, the metal support 1 is formed with a plurality (a large number) of through holes 1a penetrating through the front side and the back side. As can be seen from these drawings, a plurality of through holes 1a are provided in the central portion of the metal support 1 in the flow direction of the gas flowing through the fuel gas supply channel L1 and in the direction transverse thereto. At least the flow of fuel gas is possible. A gas shield is provided at the portion where the through holes 1a are not formed (the portion on the outer peripheral side in the transverse direction of the metal support 1). In the fuel cell of the present invention, the gas flowing through the through holes 1a is specifically the fuel gas described above and water vapor generated by the power generation reaction in the fuel cell R. FIG. FIG. 5 shows gases (CH ₄ , H ₂ , CO, H ₂ O, CO ₂ ) flowing through the through hole 1a in this way.

As a material for the metal support 1, a material having excellent electronic conductivity, heat resistance, oxidation resistance and corrosion resistance is used. For example, ferritic stainless steel, austenitic stainless steel, nickel-based alloy, etc. are used. In particular, alloys containing chromium are preferably used. In the present embodiment, the metal support 1 uses an Fe—Cr alloy containing 18% by mass or more and 25% by mass or less of Cr. An Fe—Cr alloy containing 0.15% by mass or more and 1.0% by mass or less of Ti, an Fe—Cr alloy containing 0.15% by mass or more and 1.0% by mass or less of Zr, Ti and Zr An Fe—Cr alloy with a total Ti and Zr content of 0.15% by mass or more and 1.0% by mass or less, and an Fe—Cr alloy containing 0.10% by mass or more and 1.0% by mass or less of Cu Any of the alloys is particularly preferred.

The metal support 1 is plate-shaped as a whole. It should be noted that it is also possible to bend the plate-like metal support 1 and deform it into, for example, a box shape or a cylindrical shape for use.

A metal oxide layer x is provided as a diffusion suppressing layer on the surface of the metal support 1 (see FIG. 5). That is, a diffusion suppressing layer is formed between the metal support 1 and the anode electrode layer A described later. The metal oxide layer x is provided not only on the surface exposed to the outside of the metal support 1 but also on the contact surface (interface) with the anode electrode layer A. It can also be provided on the inner surface of the through hole 1a. Interdiffusion of elements between the metal support 1 and the anode electrode layer A can be suppressed by the metal oxide layer x. For example, when ferritic stainless steel containing chromium is used as the metal support 1, the metal oxide layer x is mainly chromium oxide. The metal oxide layer x containing chromium oxide as a main component suppresses the diffusion of the chromium atoms and the like of the metal support 1 to the anode electrode layer A and the electrolyte layer B. The thickness of the metal oxide layer x may be any thickness that achieves both high anti-diffusion performance and low electrical resistance.

Although the metal oxide layer x can be formed by various methods, a method of oxidizing the surface of the metal support 1 to form a metal oxide is preferably used. Alternatively, the metal oxide layer x may be applied to the surface of the metal support 1 by a spray coating method (a thermal spraying method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, a cold spray method, etc.). method), a sputtering method, a PVD method such as a PLD method, a CVD method, or the like, or may be formed by plating and oxidation treatment. Furthermore, the metal oxide layer x may contain a highly conductive spinel phase or the like.

When a ferritic stainless steel material is used as the metal support 1, YSZ (yttria-stabilized zirconia) and GDC (gadolin-doped ceria, also called CGO) used as materials for the anode electrode layer A and the electrolyte layer B are combined with heat. Expansion coefficients are close. Therefore, the fuel cell R is less likely to be damaged even when the temperature cycle of low temperature and high temperature is repeated. Therefore, it is possible to realize a fuel cell R excellent in long-term durability, which is preferable.

The through-holes 1a can be provided in the metal support 1 by mechanical, chemical or optical drilling or the like. The through holes 1a have the function of allowing gas to permeate from both the front and back sides of the metal support 1. As shown in FIG. It is also possible to use a porous metal in order to give the metal support 1 gas permeability. For example, the metal support 1 may be made of sintered metal, foamed metal, or the like.

<Fuel cell>
The fuel cell R is composed of an anode electrode layer A, an electrolyte layer B, a cathode electrode layer C, and an intermediate layer y and a reaction prevention layer z between these layers as appropriate. This fuel cell R is a solid oxide fuel cell SOFC. As described above, the fuel cell R includes the intermediate layer y and the reaction prevention layer z, so that the electrolyte layer B is sandwiched between the anode electrode layer A and the cathode electrode layer C indirectly. In terms of generating only battery power generation, it is possible to generate power by forming the anode electrode layer A on one side of the electrolyte layer B and the cathode electrode layer C on the other side.

<Anode electrode layer>
As shown in FIGS. 3 to 5, the anode electrode layer A can be provided in the state of a thin layer in an area on the front side of the metal support 1 that is larger than the area in which the through holes 1a are provided. In the case of a thin layer, the thickness can be, for example, about 1 μm to 100 μm, preferably 5 μm to 50 μm. With such a thickness, it is possible to secure sufficient electrode performance while reducing costs by reducing the amount of expensive electrode layer material used. The entire area where the through hole 1a is provided is covered with the anode electrode layer A. As shown in FIG. That is, the through hole 1a is formed inside the region of the metal support 1 where the anode electrode layer A is formed. In other words, all the through holes 1a are provided facing the anode electrode layer A. As shown in FIG.

As the material of the anode electrode layer A, composite materials such as NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, CuO-CeO ₂ and Cu-CeO ₂ can be used. In these examples, GDC, YSZ, _CeO2 can be referred to as the composite aggregate.
In addition, the anode electrode layer A can be formed by a low-temperature firing method (for example, a wet method using firing treatment in a low-temperature region without firing treatment in a high-temperature region higher than 1100 ° C.) or a spray coating method (thermal spraying method, aerosol deposition method, aerosol It is preferably formed by a method such as a gas deposition method, a powder jet deposition method, a particle jet deposition method, a cold spray method, etc.), a PVD method (sputtering method, pulse laser deposition method, etc.), a CVD method, or the like. A good anode electrode layer A can be obtained by these processes that can be used in a low temperature range without using sintering in a high temperature range higher than 1100° C., for example. Therefore, the metal support 1 is not damaged, element mutual diffusion between the metal support 1 and the anode electrode layer A can be suppressed, and an electrochemical device excellent in durability can be realized, which is preferable. Furthermore, it is more preferable to use the low-temperature firing method because the handling of the raw material is facilitated.
Also, the amount of Ni contained in the anode electrode layer A can be in the range of 35% by mass or more and 85% by mass or less. In addition, the amount of Ni contained in the anode electrode layer A is more preferably more than 40% by mass, and even more preferably more than 45% by mass, since the power generation performance can be further enhanced. On the other hand, since it becomes easy to reduce cost, it is more preferable that it is 80 mass % or less.

The anode electrode layer A has a plurality of pores (not shown) inside and on the surface in order to provide gas permeability. That is, the anode electrode layer A is formed as a porous layer. The anode electrode layer A is formed, for example, so that its denseness is 30% or more and less than 80%. The size of the pores can be appropriately selected so that the electrochemical reaction proceeds smoothly. The denseness is the ratio of the space occupied by the material constituting the layer, and can be expressed as (1-porosity), and is equivalent to the relative density.

(middle layer)
The intermediate layer y can be formed in a thin layer on the anode electrode layer A while covering the anode electrode layer A, as shown in FIG. In the case of a thin layer, the thickness can be, for example, about 1 μm to 100 μm, preferably about 2 μm to 50 μm, more preferably about 4 μm to 25 μm. With such a thickness, it is possible to secure sufficient performance while reducing costs by reducing the amount of expensive intermediate layer material used. Examples of materials for the intermediate layer y include YSZ (yttria-stabilized zirconia), SSZ (scandium-stabilized zirconia), GDC (gadolin-doped ceria), YDC (yttrium-doped ceria), and SDC (samarium-doped ceria). ceria) and the like can be used. In particular, ceria-based ceramics are preferably used.

The intermediate layer y is formed by a low-temperature baking method (for example, a wet method using a baking treatment in a low-temperature region without baking treatment in a high-temperature region higher than 1100 ° C.) or a spray coating method (thermal spraying method, aerosol deposition method, aerosol gas deposition method, etc.). method, powder jet deposition method, particle jet deposition method, cold spray method, etc.), PVD method (sputtering method, pulse laser deposition method, etc.), CVD method, or the like. These film formation processes that can be used in the low temperature range provide the intermediate layer y without the use of baking in the high temperature range higher than 1100° C., for example. Therefore, mutual diffusion of elements between the metal support 1 and the anode electrode layer A can be suppressed without damaging the metal support 1, and a fuel cell R excellent in durability can be realized. Moreover, it is more preferable to use the low-temperature firing method because the raw material can be easily handled.

The intermediate layer y has oxygen ion (oxide ion) conductivity. Further, it is more preferable to have mixed conductivity of oxygen ions (oxide ions) and electrons. The intermediate layer y having these properties is suitable for application to the fuel cell R.

(Electrolyte layer)
The electrolyte layer B is formed in a thin layer state on the intermediate layer y while covering the anode electrode layer A and the intermediate layer y. It can also be formed in the form of a thin film with a thickness of 10 μm or less.
Specifically, as shown in FIGS. 3 to 5 and the like, the electrolyte layer B is provided over (straddles) the intermediate layer y and the metal support 1 . By forming the electrochemical device in this manner and bonding the electrolyte layer B to the metal support 1, the electrochemical device as a whole can be made excellent in robustness.

Further, the electrolyte layer B is provided on the front side of the metal support 1 in an area larger than the area in which the through holes 1a are provided. That is, the through hole 1a is formed inside the region of the metal support 1 where the electrolyte layer B is formed.

Further, around the electrolyte layer B, leakage of gas from the anode electrode layer A and the intermediate layer y can be suppressed. To explain, during power generation, gas is supplied from the back side of the metal support 1 to the anode electrode layer A through the through holes 1a. At the portion where the electrolyte layer B is in contact with the metal support 1, gas leakage can be suppressed without providing a separate member such as a gasket. In this embodiment, the electrolyte layer B covers the entire circumference of the anode electrode layer A, but the electrolyte layer B may be provided on the anode electrode layer A and the intermediate layer y, and a gasket or the like may be provided around the electrolyte layer B. .

Materials for the electrolyte layer B include YSZ (yttria-stabilized zirconia), SSZ (scandium-stabilized zirconia), GDC (gadolin-doped ceria), YDC (yttrium-doped ceria), and SDC (samarium-doped ceria). , LSGM (strontium-magnesium added lanthanum gallate) and the like can be used. In particular, zirconia-based ceramics are preferably used. When the electrolyte layer B is made of zirconia-based ceramics, the operating temperature of the SOFC using the fuel cells R can be made higher than that of ceria-based ceramics. In the case of SOFC, a material such as YSZ that can exhibit high electrolyte performance even in a high temperature range of about 650 ° C. or higher is used as the material of the electrolyte layer B, and the raw fuel of the system is a hydrocarbon-based fuel such as city gas or LPG. , and a system configuration in which the raw fuel is converted to SOFC fuel gas by steam reforming or the like, it is possible to construct a highly efficient SOFC system that uses the heat generated in the SOFC cell stack to reform the raw fuel gas.

The electrolyte layer B can be formed by a low-temperature firing method (for example, a wet method using firing treatment in a low-temperature region without firing treatment in a high-temperature region exceeding 1100 ° C.) or a spray coating method (thermal spraying method, aerosol deposition method, aerosol gas deposition method, etc.). method, powder jet deposition method, particle jet deposition method, cold spray method, etc.), PVD method (sputtering method, pulse laser deposition method, etc.), CVD method, or the like. By these film forming processes that can be used in a low temperature range, the electrolyte layer B that is dense and has high airtightness and gas barrier properties can be obtained without using sintering in a high temperature range exceeding 1100° C., for example. As a result, damage to the metal support 1 can be suppressed, and interdiffusion of elements between the metal support 1 and the anode electrode layer A can be suppressed, so that a fuel cell R with excellent performance and durability can be realized. In particular, it is preferable to use a low-temperature baking method, a spray coating method, or the like, since a low-cost device can be realized. Furthermore, the use of a spray coating method is more preferable because a dense electrolyte layer with high airtightness and gas barrier properties can be easily obtained in a low temperature range.

The electrolyte layer B is densely structured in order to shield gas leakage of fuel gas and oxidizing gas and to develop high ionic conductivity. The denseness of the electrolyte layer B is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. When the electrolyte layer B is a uniform layer, it preferably has a denseness of 95% or more, more preferably 98% or more. Further, when the electrolyte layer B is composed of a plurality of layers, it is preferable that at least a part of them contain a layer (dense electrolyte layer) having a density of 98% or more, such as 99%. It is more preferable to include the above layer (dense electrolyte layer). When such a dense electrolyte layer is included in a part of the electrolyte layer, even when the electrolyte layer is composed of a plurality of layers, a dense electrolyte layer with high airtightness and gas barrier properties is formed. Because it can be done easily.

(Reaction prevention layer)
The reaction prevention layer z can be formed on the electrolyte layer B in the form of a thin layer. In the case of a thin layer, the thickness can be, for example, about 1 μm to 100 μm, preferably about 2 μm to 50 μm, more preferably about 3 μm to 15 μm. With such a thickness, it is possible to reduce costs by reducing the amount of the expensive reaction-preventing layer material used, while ensuring sufficient performance. As the material of the reaction prevention layer z, any material that can prevent the reaction between the components of the electrolyte layer B and the cathode electrode layer C can be used. For example, a ceria-based material is used. A material containing at least one element selected from the group consisting of Sm, Gd and Y is preferably used as the material for the reaction prevention layer z. At least one element selected from the group consisting of Sm, Gd and Y is contained, and the total content of these elements is preferably 1.0% by mass or more and 10% by mass or less. By introducing the reaction-preventing layer z between the electrolyte layer B and the cathode electrode layer C, the reaction between the constituent material of the cathode electrode layer C and the constituent material of the electrolyte layer B is effectively suppressed (diffusion suppression), Long-term stability of the performance of the fuel cell R can be improved. If the reaction prevention layer z is formed by appropriately using a method that can be formed at a treatment temperature of 1100° C. or less, damage to the metal support 1 can be suppressed, and element interaction between the metal support 1 and the anode electrode layer A can be prevented. It is preferable because diffusion can be suppressed and a fuel cell R having excellent performance and durability can be realized. For example, low-temperature firing method (for example, wet method using firing treatment in low temperature range without firing treatment in high temperature range exceeding 1100 ° C.), spray coating method (thermal spraying method, aerosol deposition method, aerosol gas deposition method, powder jet deposition method, particle jet deposition method, cold spray method, etc.), PVD method (sputtering method, pulse laser deposition method, etc.), CVD method, etc. can be used as appropriate. In particular, it is preferable to use a low-temperature baking method, a spray coating method, or the like, since a low-cost device can be realized. Furthermore, it is more preferable to use the low-temperature firing method because the handling of the raw material is facilitated.

(Cathode electrode layer)
The cathode electrode layer C can be formed as a thin layer on the electrolyte layer B or the reaction prevention layer z. In the case of a thin layer, the thickness can be, for example, about 1 μm to 100 μm, preferably 5 μm to 50 μm. With such a thickness, it is possible to secure sufficient electrode performance while reducing the amount of expensive cathode electrode layer material used to reduce costs. As a material for the cathode electrode layer C, for example, composite oxides such as LSCF and LSM, ceria-based oxides, and mixtures thereof can be used. In particular, the cathode electrode layer C preferably contains a perovskite oxide containing two or more elements selected from the group consisting of La, Sr, Sm, Mn, Co and Fe. The cathode electrode layer C composed of the above materials functions as a cathode.

When the cathode electrode layer C is formed by appropriately using a method that can be formed at a processing temperature of 1100° C. or less, damage to the metal support 1 can be suppressed and the metal support 1 and the anode electrode layer A can be formed. It is preferable because it is possible to suppress interdiffusion of elements and realize a fuel cell R having excellent performance and durability. For example, low-temperature firing method (for example, wet method using firing treatment in low temperature range without firing treatment in high temperature range exceeding 1100 ° C.), spray coating method (thermal spraying method, aerosol deposition method, aerosol gas deposition method, powder jet deposition method, particle jet deposition method, cold spray method, etc.), PDV method (sputtering method, pulse laser deposition method, etc.), CVD method, etc. can be used as appropriate. In particular, it is preferable to use a low-temperature baking method, a spray coating method, or the like, since a low-cost device can be realized. Furthermore, it is more preferable to use the low-temperature firing method because the handling of the raw material is facilitated.

In the fuel cell single cell unit U, electrical conductivity is ensured between the metal support 1 and the anode electrode layer A and between the cathode electrode layer C and the separator 7 . Moreover, an insulating coating may be formed on a necessary portion of the surface of the metal support 1 as necessary. Furthermore, the independence of the fuel gas supply path L1 and the oxidizing gas supply path L2 is ensured, and gas does not leak in the direction crossing these supply paths L1 and L2.

<Power generation with fuel cells>
The fuel cell R generates power by being supplied with both the fuel gas and the oxidizing gas. By supplying both gases to each electrode layer (anode electrode layer A and cathode electrode layer C) of the fuel cell R in this way, as shown in _FIG . - to generate oxygen ions O ^2- . The oxygen ions O ²⁻ move to the anode electrode layer A through the electrolyte layer B. In the anode electrode layer A, the fuel gas for power generation (hydrogen H ₂ and carbon monoxide CO) respectively reacts with oxygen ions O ^2- to generate water vapor H ₂ O, carbon dioxide CO ₂ and electrons e-. be. Due to the above reaction, an electromotive force is generated between the anode electrode layer A and the cathode electrode layer C, and power is generated.

The above is an explanation of the basic configuration of the fuel cell according to the present invention. Hereinafter, mainly FIGS. will be described with reference to

<Internal reforming catalyst layer>
In the fuel cell single cell unit U, a fuel gas supply path L1 for supplying a gas containing hydrogen to the anode electrode layer A is formed between the metal separator 7 and the metal support 1 . As indicated by arrows in FIGS. 2, 3 and 4, the gas flowing through the fuel gas supply path L1 is supplied from the side of the gas manifold 40a in its longitudinal direction. In FIG. 5, it is the front and back direction of the paper surface. Hydrogen for power generation reaction is supplied to the anode electrode layer A through the through-holes 1 a provided through the front and back of the metal support 1 .

Here, the power generation reaction in the fuel cell R is as described above. As a result of this reaction, water vapor _H 2 flows from the anode electrode layer A to the through hole 1a and the fuel gas supply path L1. O is released. As a result, the fuel gas supply path L1 of the present invention serves as a supply section for supplying fuel gas containing hydrogen _H2 to the anode electrode layer A, and at the same time serves as a discharge section for water vapor _H2O .

Therefore, in the present invention, as shown in FIGS. 3 to 5, an internal reforming catalyst layer D is provided on the surface of the metal separator 7 on the side of the fuel gas supply path L1 (the surface on the side of the metal support 1).
In the fuel gas supply path L1, in addition to hydrogen _H2 obtained by external reforming, raw fuel gas to be reformed (gas before reforming: specifically reducing gas mainly composed of methane _CH4 ) However, by returning the water vapor H ₂ O generated in the anode electrode layer A to the fuel gas supply path L1, it can flow into the fuel gas supply path L1 and reform the raw fuel gas. Naturally, the generated hydrogen H ₂ and carbon monoxide CO can be supplied to the anode electrode layer A through the through holes 1a on the downstream side and used for power generation.

As the material of the internal reforming catalyst layer D, for example, a large number of ceramic porous granules holding a reforming catalyst such as nickel, ruthenium or platinum can be formed in an air permeable state.
The amount of Ni contained in the internal reforming catalyst layer D can be in the range of 0.1% by mass or more and 50% by mass or less. When the internal reforming catalyst layer D contains Ni, the Ni content is more preferably 1% by mass or more, and even more preferably 5% by mass or more. This is because by doing so, higher internal reforming performance can be obtained.
On the other hand, when the internal reforming catalyst layer D contains Ni, the Ni content is more preferably 45% by mass or less, and even more preferably 40% by mass or less. By doing so, the cost of the fuel cell device can be further reduced. It is also preferable to support Ni on a carrier.
In addition, the internal reforming catalyst layer D can be formed by a low-temperature firing method (for example, a wet method using a firing process in a low-temperature range without firing in a high-temperature range higher than 1100 ° C.) or a spray coating method (thermal spraying or aerosol deposition). method, aerosol gas deposition method, powder jet deposition method, particle jet deposition method, cold spray method, etc.), PVD method (sputtering method, pulse laser deposition method, etc.), CVD method, etc. preferable. By these processes that can be used in a low temperature range, a good internal This is because the reforming catalyst layer D can be formed and the fuel cell single cell unit U having excellent durability can be realized. Further, it is preferable to form the internal reforming catalyst layer D after forming the diffusion suppression layer x on the surfaces of the metal support 1 and the metal separator 7, since scattering of Cr from the metal support 1 and the metal separator 7 can be suppressed. .

Such an internal reforming catalyst layer D preferably has a thickness of, for example, 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more. This is because such a thickness increases the contact area with the fuel gas and water vapor, thereby increasing the internal reforming rate. Also, the thickness is preferably 500 μm or less, more preferably 300 μm or less, and even more preferably 100 μm or less, for example. This is because such a thickness can reduce the amount of the expensive internal reforming catalyst material used, thereby reducing costs.

Returning to FIG. 5 again, the steam reforming reaction in this internal reforming catalyst layer D will be briefly described. As shown in the figure, by providing an internal reforming catalyst layer D in the fuel cell single cell unit U, CH ₄ contained in the raw fuel gas supplied to the fuel gas supply path L1 is reformed as follows. Thus, hydrogen H ₂ can be produced as a fuel gas for power generation.

[Chemical 1]
_CH4 + _H2O →CO+ _3H2
[Chemical 2]
CO+ _H2O → _CO2 + _H2
[Chemical 3]
_CH4 + _2H2O → _CO2 + _4H2

The temperature of this fuel gas supply path L1 (internal reforming catalyst layer D) is practically 600° C. to 900° C., which is the operating temperature of the fuel cell R.

In the present invention, the fuel gas supply path L1 flows from the supply side of the mixed gas to the discharge side, and the anode electrode of the gas containing hydrogen H2 is supplied to the plurality (a large number) of through holes _1a provided therebetween. Distribution to layer A takes place. Then, at least steam reforming is performed by returning the steam H ₂ O generated in the anode electrode layer A to the internal reforming catalyst layer D, and hydrogen and carbon monoxide, which are fuel gases for power generation, are generated, and the downstream side Power generation fuel gas containing hydrogen H ₂ can be supplied to the anode electrode layer A from the through-hole 1a located at . Therefore, such a gas path is called an internal reformed fuel supply path L3, the discharge side of the generated steam H ₂ O is called a discharge part L3a, and the supply side of internally reformed hydrogen H ₂ is a supply part Call it L3b. This discharge part L3a is a steam supply path. Note that the discharge part L3a can also serve as the supply part L3b at the same time, and the supply part L3b can also serve the function as the discharge part L3a at the same time.

The above is the device on the supply side of the fuel gas. In the configuration using fuel, the steam generated by power generation is consumed in steam reforming, so the load on the condenser 32b, which should be provided for condensation of the steam contained in the anode off-gas described above, is reduced. As a result, the fuel cell device Y according to the present invention is also advantageous from this point of view.

Ingenuity of Position of Internal Reforming Catalyst Layer The fuel cell module M is formed in a substantially square box shape when viewed from the top, and the flow direction of the fuel gas and the oxidizing gas is set to one specific direction. In FIG. 4, this direction is upward to the right.

The position where the internal reforming catalyst layer D is provided is provided to supply fuel gas to the anode electrode layer A and to discharge water vapor generated in the anode electrode layer A to the fuel gas supply path L1. The internal reforming catalyst layer D is limited to a position on the downstream side from the same position as the most upstream through hole 1a in the flow direction of the fuel gas.
By providing the internal reforming catalyst layer D from such a position, the water vapor generated in the anode electrode layer A can be effectively used according to the object of the present invention.

Arrangement of Turbulence Promoter As shown in FIGS. 1, 3 and 4, the fuel gas supply path L1 for supplying the fuel gas to the anode electrode layer A is provided with a turbulence promoter E for disturbing the flow in this path. It is
More specifically, on the surface opposite to the surface on which the fuel cells R are formed, which is the fuel gas inflow side of the through-holes 1a formed through the metal support 1, the net-like body Ea is provided. Specifically, the mesh Ea is formed by attaching a lath metal or a metal wire mesh onto the metal support 1 . As a result, the hydrogen-containing gas flowing through the fuel gas supply path L1 is disturbed by the mesh Ea, inducing a flow direction component toward the through-holes 1a and a flow out of the through-holes 1a. Supply to the layer A and derivation of water vapor from the anode electrode layer A can be favorably caused.

<Another embodiment>
(1) In the above embodiment, the fuel cell is an oxide ion conductive solid oxide fuel cell. can be employed in the proton-conducting type as well, in that the fuel gas, which is a reducing gas, reaches the anode electrode layer A satisfactorily. Here, in the case of the proton-conducting type, the water vapor required for the internal reforming catalyst layer D is supplied from the outside. An excess amount of water vapor is supplied.

(2) In the above embodiment, the internal reforming catalyst layer D is provided on the surface of the metal separator 7 constituting the fuel gas supply path L1. It may be provided on the surface opposite to the side, or may be provided in the through hole 1a. That is, internal reforming can be favorably induced by providing at least part of the inner surface of the fuel cell single cell unit U so as to be in contact with the flow path serving as the fuel gas supply path L1.

(3) In the above embodiment, the turbulence promoter E is formed of the mesh Ea and attached to the surface of the metal support 1. A large number of obstacles Eb may be arranged to disturb the flow of the fuel gas supply path L1 as long as it has a directing function. The obstacle Eb may be of any shape, such as a spherical shape, a triangular pyramid shape, or a square columnar shape. FIG. 6 shows an example in which the obstacle Eb is spherical.

(4) In the above embodiment, the internal reforming catalyst layer D and the turbulence promoter E are described as being independent. An internal reforming catalyst layer D may be provided on at least part of the body Eb. An example of this is shown in FIG.
That is, by providing the internal reforming catalyst layer D on at least a part (the surface in the illustrated example) of the turbulent flow promoter E, the turbulent flow promoter E is arranged to achieve both turbulence promotion and internal reforming. Both functions can be exhibited.

(5) In the above embodiment, the steam contained in the anode off-gas was used for steam reforming. The heat of combustion components (hydrogen, carbon monoxide, etc.) may be recovered.

(6) As the material of the metal support 1, a metal oxide having conductivity can be used.
For example, metal oxides such as (La, Ca)CrO ₃ (calcium-doped lanthanum chromite) can be used.

(7) In the embodiments described so far, the metal support 1 is a flat plate member, but the metal support 1 may be made up of a plurality of members and may have a structure in which the fuel gas supply path L1 is formed therein. FIG. 8 shows an example corresponding to FIG. In this example, a combination of a flat plate member 72 and a U-shaped member 73 constitutes the metal support 1, and a mesh Ea (E) serving as a turbulence promoter is provided inside the fuel gas supply path L1 formed in the cylinder. An internal reforming catalyst layer D is also formed on the outer surface thereof. In FIG. 7, reference numeral 77 denotes a fuel gas discharge hole provided at the tip of the metal support 1 in the flow direction of the fuel gas. Furthermore, 78 is the through hole explained so far. In this example, by making the separator CP functioning as a current collector plate gas permeable, the oxidizing gas can pass through the oxidizing gas supply path L2 formed in the separator CP and be supplied to the cathode electrode layer C. can.

(8) In the embodiments described so far, the external reformer 34 is provided, and at least a part of the raw fuel gas is reformed by the external reformer 34 to produce the fuel that is provided in the fuel cell single cell unit U. Although an example in which the gas containing hydrogen is supplied to the gas supply path L1 has been shown, in the present invention, the flow of gas between the fuel gas supply path L1 and the anode electrode layer A can be promoted by the turbulence promoter E. Alternatively, the raw fuel gas required for power generation may be reformed in the internal reforming catalyst layer D provided in the fuel gas supply path L1 without providing an external reformer. That is, hydrogen (reformed gas) does not need to flow through the entire fuel gas supply path L1 provided in the fuel cell single cell unit U.

(9) In the above embodiment, the anode electrode layer A is arranged between the metal support 1 and the electrolyte layer B, and the cathode electrode layer C is arranged on the side opposite to the metal support 1 when viewed from the electrolyte layer B. A configuration in which the anode electrode layer A and the cathode electrode layer C are arranged in reverse is also possible. In other words, a configuration is also possible in which the cathode electrode layer C is arranged between the metal support 1 and the electrolyte layer B, and the anode electrode layer A is arranged on the side opposite to the metal support 1 when viewed from the electrolyte layer B. In this case, the positional relationship between the reducing gas supply path L1 and the oxidizing gas supply path L2 is reversed, and as described above, the reducing gas supply path L1 side (in this case, the lower side of the metal separator 7) The object of the present invention can be achieved by providing the internal reforming catalyst layer D and the turbulence promoter in the .

(10) In the above embodiment, an example of the case of performing a steam reforming reaction of methane was shown, but partial combustion (oxidation) reforming reaction other than steam reforming reaction, dry reforming reaction, and their respective fuels It is also possible to carry out a fuel reforming reaction that combines reforming reactions.

(11) In the above embodiment, an example of using a hydrocarbon gas such as city gas (gas containing ethane, propane, butane, etc. with methane as the main component) is used as the raw fuel gas. Hydrocarbons such as natural gas, naphtha and kerosene, alcohols such as methanol and ethanol, and ethers such as DME can also be used as raw fuel gases. In the description so far, the gas supplied to the anode electrode layer is called a reducing gas. gas. This type of gas includes hydrocarbons such as hydrogen, carbon monoxide, and methane in the case of an oxide ion-conducting fuel cell that operates in a relatively high temperature range, such as a solid oxide fuel cell.

(12) In the above embodiment, the intermediate layer y is provided between the anode electrode layer A and the electrolyte layer B, and the reaction prevention layer z is provided between the electrolyte layer B and the cathode electrode layer C. However, it is also possible to adopt a configuration in which no intervening layer such as the intermediate layer y or the reaction prevention layer z is interposed between the electrode layer and the electrolyte layer, or only one of the intervening layers may be installed. Also, the number of intervening layers can be increased as needed.

(13) In the above embodiment, the case where the metal oxide layer x is provided as the diffusion suppressing layer on the surface of the metal support 1 has been described. Alternatively, the metal oxide layer x can be a plurality of layers. It is also possible to provide a diffusion suppression layer different from the metal oxide layer.

It should be noted that the configurations disclosed in the above embodiments (including other embodiments, the same shall apply hereinafter) can be applied in combination with configurations disclosed in other embodiments as long as there is no contradiction. The embodiments disclosed in this specification are exemplifications, and the embodiments of the present invention are not limited thereto, and can be modified as appropriate without departing from the object of the present invention.

1: metal support (support)
1a: Through hole 7: Metal separator (separator)
34: External reformer 38: Inverter 72: Flat plate member 73: U-shaped member 78: Through hole A: Anode electrode layer B: Electrolyte layer C: Cathode electrode layer CP: Current collector (separator)
D: Internal reforming catalyst layer E: Turbulence promoter Ea: Reticulated body (turbulence promoter)
Eb: Obstacle (turbulence promoter)
L1: reducing gas supply path L2: oxidizing gas supply path M: fuel cell module R: fuel cell unit U: fuel cell single cell unit Y: fuel cell device

Claims (18)

a fuel cell in which an anode electrode layer and a cathode electrode layer are formed with an electrolyte layer sandwiched therebetween;
A structure capable of forming a fuel cell single cell unit, comprising a fuel gas supply path for supplying a reducing gas to the anode electrode layer and an oxidizing gas supply path for supplying an oxygen-containing gas to the cathode electrode layer. and
The fuel gas supply path is provided with an internal reforming catalyst layer that reforms the raw fuel gas and a turbulence promoter that disturbs the flow in the fuel gas supply path,
The fuel cell is formed in layers on a support,
A plurality of through-holes penetrating through the support are provided,
The anode electrode layer is provided on one surface of the support, and the fuel gas supply path is provided along the other surface, having an inlet and an outlet on the other surface side ,
The plurality of through-holes return water vapor generated in the anode electrode layer to the fuel gas supply channel, and supply the gas reformed in the internal reforming catalyst layer from the fuel gas supply channel to the anode electrode layer. battery structure. a fuel cell in which an anode electrode layer and a cathode electrode layer are formed with an electrolyte layer sandwiched therebetween;
A structure capable of forming a fuel cell single cell unit, comprising a fuel gas supply path for supplying a reducing gas to the anode electrode layer and an oxidizing gas supply path for supplying an oxygen-containing gas to the cathode electrode layer. and
The fuel gas supply path is provided with an internal reforming catalyst layer that reforms the raw fuel gas and a turbulence promoter that disturbs the flow in the fuel gas supply path,
comprising at least one separator separating the fuel gas supply channel and the oxidizing gas supply channel;
The fuel cell is formed in layers on a support,
A plurality of through-holes penetrating through the support are provided,
The anode electrode layer is provided on one surface of the support, and a gas supply passage having an inlet and an outlet on the other surface side, wherein the fuel gas supply passage along the other surface is connected to the support and the gas supply passage. provided between the separator,
A fuel cell structure in which the internal reforming catalyst layer is provided on at least a portion of the separator on the side of the fuel gas supply path. 2. The fuel cell structure according to claim 1, wherein the internal reforming catalyst layer is provided on at least part of the inner surface of the fuel gas supply passage. 2. The fuel cell structure according to claim 1, wherein said internal reforming catalyst layer is provided inside said through hole. comprising at least one separator separating the fuel gas supply channel and the oxidizing gas supply channel;
5. The fuel cell structure according to claim 1, wherein the internal reforming catalyst layer is provided on at least a portion of the separator on the fuel gas supply path side. 6. The fuel cell structure according to any one of claims 1 to 5, wherein the reforming catalyst contained in the internal reforming catalyst layer is a metal-supported catalyst. The fuel cell structure according to any one of claims 1 to 6, wherein the reforming catalyst contained in said internal reforming catalyst layer is a catalyst containing Ni. 8. The fuel cell structure according to any one of claims 1 to 7, wherein the turbulence promoter is a mesh. 6. The fuel cell structure according to any one of claims 1 and 3 to 5, wherein the turbulence promoter is a net-like body, and the net-like body is provided on the other side of the fuel gas supply passage. 8. The fuel cell structure according to any one of claims 1 to 7, wherein said turbulence promoters are a plurality of obstacles arranged in said fuel gas supply passage. 11. The fuel cell structure according to any one of claims 1 to 10, wherein a reforming catalyst is carried on at least a part of the surface of said turbulence promoter to form said internal reforming catalyst layer. 6. The fuel cell structure according to any one of claims 1 and 3 to 5, wherein said support is formed using a metal material. 13. The fuel cell structure according to any one of claims 1 to 12, wherein the turbulence promoter is formed using a metal material. 6. The fuel cell structure according to claim 2, wherein said separator is formed using a metal material. 15. The fuel cell structure according to any one of claims 1 to 14, wherein said fuel cell is a solid oxide fuel cell. comprising a plurality of fuel cell structures according to any one of claims 1 to 15,
The oxidizing gas supply path of one of the fuel cell single cell units supplies the oxygen-containing gas to the cathode electrode layer of the other fuel cell single cell unit adjacent to the one fuel cell single cell unit. fuel cell module. 17. A fuel cell apparatus comprising at least the fuel cell module according to claim 16 and an external reformer, and comprising a fuel supply section for supplying the raw fuel gas to the fuel cell module. 17. A fuel cell device comprising at least the fuel cell module according to claim 16 and an inverter for extracting power from the fuel cell module.

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